Key Lime Pi Tart




Introduction: Key Lime Pi Tart

About: I'm just a guy that knows stuff about things.

When asked what kinds of pie I like, I reply with a quote from my grandfather.  "I only like two kinds of pie, hot pie and cold pie."  Truer words have never been spoken.

However, key lime pie instantly became my favorite pie on a trip the Florida Keys during my early teens.  When I got home I decided I had to learn how to make it on my own.  Being the mid-90's I couldn't jump on Google and do a quick recipe search, but I could still query the masses geek style.  I sent my recipe request to on usenet and got back a great recipe and some tips from a fellow lover of the pie.*  That recipe became my first "signature" recipe.  I've made some tweaks over the years and now I'd like to share it with all of you.

Since this was the first recipe I learned to make on my own without parental guidance I've tried to make this instructable cover every step in detail.  I've also included some tips at the end.  I'm hoping these extra details might inspire another young food lover to try his hand at cooking.

*Thank you, Google for archiving all of usenet.  Can't believe I actually found my original post from 1996.

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Step 1: Ingredients

Here are the ingredients you'll need for each component if you're going to make it all from scratch.  You can get some of these items pre-made as well.  See the tips section for some comments.

8 Graham Crackers
4 Tbsp Butter

Pie Filling:
1 14oz Can Sweetened Condensed Milk
5 Egg Yolks
5 oz (1/2 cup + 2 Tbsp) Key Lime Juice

Whipped Cream:
1 cup Heavy Whipping Cream
1 Tbsp Sugar

Step 2: Tools

Here are the tools you'll need.  Certainly you can substitute for other tools if needed.  See the tips section for some comments.

Paddle Attachment
Whisk Attachment
Ziploc Bag
Tart Pan
Microwaveable Bowl (Not Shown)

Step 3: Crust


8 Graham Crackers (16 Squares)
4 Tbsp (1/4 cup) Butter

1) Preheat oven to 350F
2) Cut a circle of parchment paper to cover the bottom of the tart pan*
3) Put the graham crackers in the ziploc bag
4) Smash with the pan until the crumbs are about the size of sand
5) Melt the butter in the microwavable bowl
6) Mix the cracker crumbs and butter until the mixture is evenly combined
7) Dump the crumbs on top of the parchment in the bottom of the tart pan
8) Roughly spread the crumbs to cover the pan (hands work best)
9) Form a well defined edge around the sides of the pan
10) Distribute the remaining crumbs across the bottom of the pan
11) Bake the crust for 8 minutes
12) Cool for at least 10 minutes before adding the filling

*To cut a circle of parchment for a pan is quite simple.  First, fold the parchment paper as you would for a paper snow flake (4 folds for me).  Second, measure from the edge of the pan to the center with the parchment triangle.  Finally, cut the parchment to the measured length and unfold.

Step 4: Pie Filling


1 14oz Can Sweetened Condensed Milk
5 oz (1/2 cup + 2 Tbsp) Key Lime Juice
5 Egg Yolks

1) Preheat oven to 375F
2) Separate the eggs, discard the whites*
3) Add the sweetened condensed milk
4) Add the key lime juice
5) Mix on low speed until the streaks of yellow from the yolks are fully mixed in
6) Pour the filling into the cooled crust
7) Spread evenly with a spatula
8) Tap gently to remove air bubbles
9) Bake for 11 minutes
10) Cool on a rack until about room temperature (approximately 1 hour)
11) Chill in the refrigerator until chilled through (approximately 1 hour)

*The simplest way to separate eggs is to first crack the egg.  Then pour the egg onto your fingers, leaving a small space between each finger.  The egg white will drain through your fingers and you'll be left with the yolk only.

Step 5: Whipped Cream


1 cup Heavy Whipping Cream
1 Tbsp Sugar

1) Put your mixing bowl and whisk in the freezer for 10-15 minutes*
2) Combine the cream and sugar in the mixing bowl
3) Beat on medium-high speed until the whipped cream is firm enough to stand in peaks

Keeping the cream and your tools cold will help form the whipped cream quicker and prevent the fats from melting.  If you mix too long your whipped cream will turn to butter.  Which, while tasty, doesn't go well with the pie.

Step 6: Decoration + Serving


Decorating is completely up to you.  Here are some suggestions of things that pair well with the tart to get you started.

Fresh Berries
Candied Key Lime Slices

My personal favorites are mint and candied lime slices.  The berries are delicious, though, when you can get really tasty fresh berries.

To make the candied lime slices cut slices of lime as thin as you can.  With a very sharp knife you should be able to get them under 1/16" with some practice.  Then dust the slices with sugar.  The lime slices still have some bite to them, but the sugar makes them very tasty.  And, since they're so thin you can eat them peel and all.

My Decorations:

For this instructable I decorated the tart with a Pi Day theme.  Each of the berry columns is a digit of pi in binary-coded decimal .  You read them from the exterior to the interior going clockwise around the tart.  Here's a brief rundown on how I came up with the pattern.

3.14159265358  [12 Digits of Pi]
0.00001000001  [Exterior - Most Significant Bit]
1.10111001110  [Interior - Lease Significant Bit]

Blackberries are 1's and raspberries are 0's.

So, there you have it.  Nerdarific!


Serving is super simple. Slice the tart into twelve slices (this stuff is very rich). Between the berries works great if you're following my lead. Spoon on some whipped cream. Garnish with a bit of mint. Consume. Repeat.

Step 7: Tips

Okay, you've got the basics down.  Here are some tips to make your life a little easier.


Key Limes - Key limes are much different from standard (Persian ) limes that you'd use for most everything else.  Most notably they're much smaller, but the flavor differences are what's most important.  Key limes are nicely tart  and have a more complex flavor than Persian limes.  Definitely don't substitute regular lime juice in this recipe, you won't be pleased.

Key Lime Juice - For this tart I went homemade all the way, juicing my own limes.  I wouldn't recommend it.  It takes forever, my hands hurt when I was done and the product isn't really much better than using bottled juice.  On that note, I'd suggest Nellie and Joe's Key West Lime Juice .  Tastes great and makes a super tasty pie.

Crust - You can definitely use a pre-made crust.  They taste pretty good and its a good way to cut prep time.  Go with an 8" regular crust, otherwise the filling won't be enough.  For an 8" crust you'll want to bake for 15 minutes to get the custard cooked through.  If you want to use a 9" deep crust double the recipe, lower the baking temp to 300F and bake for 30 minutes.

Whipped Cream - You can use the canned whipped cream, but I find it's a bit sweeter than I like and not as dense.  For this recipe I use less sugar which helps to balance out the richness of the pie itself.  You can also use honey for sweetening, which adds a nice flavor twist.  But, please, please, please don't use artificial whipped topping.  It just doesn't make sense after you've put in the effort to make the pie.


I've made this recipe completely by hand before, even whipping the cream, and it turns out great.  Granted, it takes more time and lot more effort, but don't let that stop you from making this delicious recipe.

Tart Pan - Get one that's non-stick and has a removable bottom.  It'll make your life easier all around.

Paddle - The paddle that comes with a KitchenAid stand mixer works okay.  However, it has a tendency to leave behind some of the mixture on the sides of the bowl.  This forces you to stop working to scrape down the bowl.  Enter the Beater Blade .  This great tool does the scraping while it's mixing.  Awesome to have if you use your mixer a lot.


Baking - Don't over-bake your tart.  If you start to see bubbling on the surface it's getting too hot.  Take it out immediately.  It'll still be great though, definitely don't toss it.

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    7 Discussions


    9 years ago on Introduction

    Wow that looks delishious! What high end bakery sells those?!


    9 years ago on Introduction

    EXCELLENT instructable and great photos. Looking forward to trying on my own, thanks for posting!


    9 years ago on Introduction

    Great recipe for throwing together after lunch and treating yourself after dinner. For people who want even more tartness, add in a couple teaspoons of lime zest. For a wonderful summertime treat, freeze the cut pie wedges and eat them out of hand, no fork required. And of course, thank you for the in-depth and very well written 'ible.

    PS: Fight the urge to add green food coloring to the filling or else you'll hear the food police knocking at your door


    Reply 9 years ago on Introduction

    Awesome tips, Mama! Thanks much.

    You're absolutely right about the green food coloring. And I'd add that meringue should never touch a key lime pie either.